The author describes the larval development of Hymenolepis diminuta (Rud., 1819) in Strongylopsalis mathurinii (Dermaptera) and Alphitobius piceus (Coleoptera), two new intermediate hosts. The pattern of development of the cysticercoids in both hosts is similar, although some differences in detail were observed. The cysticercoids developed in the earwigs are relatively larger than those obtained from the beetles. The total development may be completed in nine days in the earwigs instead of the usual twelve days. The author suggests that Strongylopsalis mathurinii a very commom insect living in rats food is a suitable host for experimental studies on H. diminuta development.